Move DocumentationLanguageService to a separate module

Package.swift

@@ -237,7 +237,22 @@ var targets: [Target] = [
     swiftSettings: globalSwiftSettings
   ),
 
-  // MARK: DocCDocumentation
+  // MARK: DocumentationLanguageService
+
+  .target(
+    name: "DocumentationLanguageService",
+    dependencies: [
+      "BuildServerIntegration",
+      "DocCDocumentation",
+      "LanguageServerProtocol",
+      "SKUtilities",
+      "SourceKitLSP",
+      "SemanticIndex",
+      .product(name: "Markdown", package: "swift-markdown"),
+    ],
+    exclude: [],
+    swiftSettings: globalSwiftSettings
+  ),
 
   .target(
     name: "DocCDocumentation",
@@ -263,6 +278,7 @@ var targets: [Target] = [
     dependencies: [
       "BuildServerIntegration",
       "ClangLanguageService",
+      "DocumentationLanguageService",
       "LanguageServerProtocol",
       "SKLogging",
       "SKOptions",

Sources/ClangLanguageService/ClangLanguageService.swift

@@ -24,10 +24,6 @@ package import SwiftSyntax
 import TSCExtensions
 package import ToolchainRegistry
 
-#if canImport(DocCDocumentation)
-import DocCDocumentation
-#endif
-
 #if os(Windows)
 import WinSDK
 #endif
@@ -497,16 +493,16 @@ extension ClangLanguageService {
     return try await forwardRequestToClangd(req)
   }
 
-  #if canImport(DocCDocumentation)
   package func doccDocumentation(_ req: DoccDocumentationRequest) async throws -> DoccDocumentationResponse {
     guard let sourceKitLSPServer else {
       throw ResponseError.unknown("Connection to the editor closed")
     }
 
     let snapshot = try sourceKitLSPServer.documentManager.latestSnapshot(req.textDocument.uri)
-    throw ResponseError.requestFailed(doccDocumentationError: .unsupportedLanguage(snapshot.language))
+    throw ResponseError.requestFailed(
+      "Documentation preview is not available for \(snapshot.language.description) files"
+    )
   }
-  #endif
 
   package func symbolInfo(_ req: SymbolInfoRequest) async throws -> [SymbolDetails] {
     return try await forwardRequestToClangd(req)

Sources/SourceKitLSP/Documentation/DoccDocumentationHandler.swift → Sources/DocumentationLanguageService/DoccDocumentationHandler.swift

@@ -18,6 +18,7 @@ import Foundation
 package import LanguageServerProtocol
 import Markdown
 import SKUtilities
+import SourceKitLSP
 import SemanticIndex
 
 extension DocumentationLanguageService {
@@ -63,9 +64,13 @@ extension DocumentationLanguageService {
             ofDocCSymbolLink: symbolLink,
             fetchSymbolGraph: { location in
               guard let symbolWorkspace = try await workspaceForDocument(uri: location.documentUri),
-                let languageService = try await languageService(for: location.documentUri, .swift, in: symbolWorkspace)
+                let languageService = await sourceKitLSPServer.languageService(
+                  for: location.documentUri,
+                  .swift,
+                  in: symbolWorkspace
+                )
               else {
-                throw ResponseError.internalError("Unable to find Swift language service for \(location.documentUri)")
+                throw ResponseError.internalError("Unable to find language service for \(location.documentUri)")
               }
               return try await languageService.symbolGraph(forOnDiskContentsOf: location.documentUri, at: location)
             }
@@ -76,9 +81,13 @@ extension DocumentationLanguageService {
         let symbolDocumentUri = symbolOccurrence.location.documentUri
         guard
           let symbolWorkspace = try await workspaceForDocument(uri: symbolDocumentUri),
-          let languageService = try await languageService(for: symbolDocumentUri, .swift, in: symbolWorkspace)
+          let languageService = await sourceKitLSPServer.languageService(
+            for: symbolDocumentUri,
+            .swift,
+            in: symbolWorkspace
+          )
         else {
-          throw ResponseError.internalError("Unable to find Swift language service for \(symbolDocumentUri)")
+          throw ResponseError.internalError("Unable to find language service for \(symbolDocumentUri)")
         }
         let symbolGraph = try await languageService.symbolGraph(
           forOnDiskContentsOf: symbolDocumentUri,

Sources/SourceKitLSP/Documentation/DocumentationLanguageService.swift → Sources/DocumentationLanguageService/DocumentationLanguageService.swift

@@ -14,6 +14,7 @@ import Foundation
 package import IndexStoreDB
 package import LanguageServerProtocol
 package import SKOptions
+package import SourceKitLSP
 import SwiftExtensions
 package import SwiftSyntax
 package import ToolchainRegistry
@@ -52,7 +53,7 @@ package actor DocumentationLanguageService: LanguageService, Sendable {
 
   func languageService(
     for uri: DocumentURI,
-    _ language: Language,
+    _ language: LanguageServerProtocol.Language,
     in workspace: Workspace
   ) async throws -> LanguageService? {
     guard let sourceKitLSPServer else {

Sources/InProcessClient/LanguageServiceRegistry+staticallyKnownServices.swift

@@ -15,13 +15,19 @@ import LanguageServerProtocol
 package import SourceKitLSP
 import SwiftLanguageService
 
+#if canImport(DocumentationLanguageService)
+import DocumentationLanguageService
+#endif
+
 extension LanguageServiceRegistry {
   /// All types conforming to `LanguageService` that are known at compile time.
   package static let staticallyKnownServices = {
     var registry = LanguageServiceRegistry()
     registry.register(ClangLanguageService.self, for: [.c, .cpp, .objective_c, .objective_cpp])
     registry.register(SwiftLanguageService.self, for: [.swift])
+    #if canImport(DocumentationLanguageService)
     registry.register(DocumentationLanguageService.self, for: [.markdown, .tutorial])
+    #endif
     return registry
   }()
 }

Sources/LanguageServerProtocol/Error.swift

@@ -83,6 +83,9 @@ public struct ErrorCode: RawRepresentable, Codable, Hashable, Sendable {
 
   // MARK: SourceKit-LSP specific error codes
   public static let workspaceNotOpen: ErrorCode = ErrorCode(rawValue: -32003)
+
+  /// The method is not implemented in this `LanguageService`.
+  public static let requestNotImplemented: ErrorCode = ErrorCode(rawValue: -32004)
 }
 
 /// An error response represented by a code and message.
@@ -131,6 +134,10 @@ extension ResponseError {
   public static func internalError(_ message: String) -> ResponseError {
     return ResponseError(code: .internalError, message: message)
   }
+
+  public static func requestNotImplemented(_ method: any RequestType.Type) -> ResponseError {
+    return ResponseError(code: .requestNotImplemented, message: "request not implemented: \(method.method)")
+  }
 }
 
 /// An error during message decoding.

Sources/SourceKitLSP/CMakeLists.txt

@@ -26,10 +26,6 @@ add_library(SourceKitLSP STATIC
   TextEdit+IsNoop.swift
   Workspace.swift
 )
-target_sources(SourceKitLSP PRIVATE
-  Documentation/DocCDocumentationHandler.swift
-  Documentation/DocumentationLanguageService.swift
-)
 set_target_properties(SourceKitLSP PROPERTIES
   INTERFACE_INCLUDE_DIRECTORIES ${CMAKE_Swift_MODULE_DIRECTORY}
 )

Sources/SourceKitLSP/LanguageService.swift

@@ -176,9 +176,7 @@ package protocol LanguageService: AnyObject, Sendable {
   func completion(_ req: CompletionRequest) async throws -> CompletionList
   func completionItemResolve(_ req: CompletionItemResolveRequest) async throws -> CompletionItem
   func hover(_ req: HoverRequest) async throws -> HoverResponse?
-  #if canImport(DocCDocumentation)
   func doccDocumentation(_ req: DoccDocumentationRequest) async throws -> DoccDocumentationResponse
-  #endif
   func symbolInfo(_ request: SymbolInfoRequest) async throws -> [SymbolDetails]
 
   /// Return the symbol graph at the given location for the contents of the document as they are on-disk (opposed to the

Sources/SourceKitLSP/SourceKitLSPServer.swift

@@ -757,10 +757,8 @@ extension SourceKitLSPServer: QueueBasedMessageHandler {
       await self.handleRequest(for: request, requestHandler: self.declaration)
     case let request as RequestAndReply<DefinitionRequest>:
       await self.handleRequest(for: request, requestHandler: self.definition)
-    #if canImport(DocCDocumentation)
     case let request as RequestAndReply<DoccDocumentationRequest>:
       await self.handleRequest(for: request, requestHandler: self.doccDocumentation)
-    #endif
     case let request as RequestAndReply<DocumentColorRequest>:
       await self.handleRequest(for: request, requestHandler: self.documentColor)
     case let request as RequestAndReply<DocumentDiagnosticsRequest>:
@@ -1573,15 +1571,13 @@ extension SourceKitLSPServer {
     return try await documentService(for: uri).completionItemResolve(request)
   }
 
-  #if canImport(DocCDocumentation)
   func doccDocumentation(
     _ req: DoccDocumentationRequest,
     workspace: Workspace,
     languageService: LanguageService
   ) async throws -> DoccDocumentationResponse {
     return try await languageService.doccDocumentation(req)
   }
-  #endif
 
   func hover(
     _ req: HoverRequest,

Sources/SwiftLanguageService/DoccDocumentation.swift

@@ -10,20 +10,23 @@
 //
 //===----------------------------------------------------------------------===//
 
-#if canImport(DocCDocumentation)
 import BuildServerIntegration
-import DocCDocumentation
 import Foundation
 import IndexStoreDB
 package import LanguageServerProtocol
-import SemanticIndex
 import SKLogging
+import SemanticIndex
+import SourceKitLSP
 import SwiftExtensions
 import SwiftSyntax
-import SourceKitLSP
+
+#if canImport(DocCDocumentation)
+import DocCDocumentation
+#endif
 
 extension SwiftLanguageService {
   package func doccDocumentation(_ req: DoccDocumentationRequest) async throws -> DoccDocumentationResponse {
+    #if canImport(DocCDocumentation)
     guard let sourceKitLSPServer else {
       throw ResponseError.internalError("SourceKit-LSP is shutting down")
     }
@@ -100,8 +103,12 @@ extension SwiftLanguageService {
       moduleName: moduleName,
       catalogURL: catalogURL
     )
+    #else
+    throw ResponseError.requestFailed("Documentation preview is not available in this build of SourceKit-LSP")
+    #endif
   }
 
+  #if canImport(DocCDocumentation)
   private func findMarkupExtensionFile(
     workspace: Workspace,
     documentationManager: DocCDocumentationManager,
@@ -127,6 +134,7 @@ extension SwiftLanguageService {
       language: .markdown
     )?.text
   }
+  #endif
 }
 
 private struct DocumentableSymbol {
@@ -216,4 +224,3 @@ private struct DocumentableSymbol {
     return nil
   }
 }
-#endif

Tests/SourceKitLSPTests/DoccDocumentationTests.swift

@@ -21,7 +21,6 @@ import SwiftDocC
 import XCTest
 
 final class DoccDocumentationTests: XCTestCase {
-
   func testUnsupportedLanguage() async throws {
     try await renderDocumentation(
       markedText: "1️⃣",

Tests/SourceKitLSPTests/DocumentationLanguageServiceTests.swift

@@ -10,6 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#if canImport(DocCDocumentation)
 import LanguageServerProtocol
 import SKTestSupport
 import SourceKitLSP
@@ -39,3 +40,4 @@ private func assertHandles(language: Language) async throws {
   )
   XCTAssertEqual(completions, .init(isIncomplete: false, items: []))
 }
+#endif